Conventionally, the electric property of an electric component such as a surface-mount electric component that does not include a coaxial connector has been measured while the electric component is mounted on a measurement jig including a coaxial connector and a coaxial cable connects the measurement jig and a measurement device. In such a measurement, a measurement error is caused by variation in property between individual measurement jigs as well as variation in property between individual coaxial cables and measurement devices.
Measurement of the coaxial cable and the measurement device is performed while the measurement device is connected with a standard having a reference property through the coaxial cable. This allows identification of an error occurring between the head of the coaxial cable connected with the standard and the measurement device.
However, for the measurement jig, it is impossible to accurately identify an error in electric property between a connection terminal in a part at which the electric component is mounted and the coaxial connector for connecting the coaxial cable. It is also difficult to adjust measurement jigs to have identical properties. In particular, it is significantly difficult to adjust measurement jigs to have identical properties over a wide bandwidth.
To solve these problems, what is called a relative error correction method has been disclosed that performs measurement while a correction data acquisition specimen is mounted on a plurality of measurement jigs to previously derive, from variation in measurement values between the measurement jigs, an expression for correcting a relative error between a measurement jig (hereinafter referred to as a “reference jig”) and another measurement jig (hereinafter referred to as a “test jig”), and calculates, for the electric property of any given electric component, using the expression from a measurement value (test jig measurement value) measured while the electric component is mounted on the test jig, an estimation value of a measurement value (test jig measurement value) measured while the electric component is mounted on the reference jig.
For example, in a relative error correction method disclosed in Japanese Patent No. 3558086, a “relative error correction adapter” obtained by deriving, for each port, a scattering matrix obtained by synthesizing a scattering matrix of error of the reference jig and a scattering matrix for removing (canceling) error of the test jig is used as the expression for correcting the relative error between the reference jig and the test jig. The estimation value of the reference jig measurement value of the specimen is calculated by synthesizing the relative error correction adapter with a scattering matrix of the test jig measurement value of an optional specimen. The relative error correction adapter can be calculated from a result of measuring at least three one-port standard specimens with both of the reference jig and the test jig for each port.
The relative error correction method disclosed in Japanese Patent No. 3558086 employs a relative error correction circuit network model derived by assuming that there exists only a signal line port connected with a signal line related to application or detection of a high frequency signal. Influence of non signal line ports such as GND and power ports other than signal line ports is omitted in the relative error correction circuit network model. However, in reality, any difference exists between non-RF ports included in measurement jigs, and thus such omission is a major factor of a residual error in relative error correction.
To solve such a problem, Japanese Patent No. 4009876 discloses a relative error correction method that measures a non-RF port through the test jig and calculates the estimation value of the reference jig measurement value obtained without measurement of the non-RF port. The number of ports included in a standard specimen to be prepared for connection with RF ports and necessary for performing the relative error correction method disclosed in Japanese Patent No. 4009876 needs to equal the number of non-RF ports.
In the relative error correction methods disclosed in Patent Japanese Patent No. 3558086 and Japanese Patent No. 4009876, a signal (hereinafter referred to as an “inter-port leakage signal”) transferred from a measurement jig not through a DUT but directly between ports within the measurement jig is omitted in the relative error correction circuit network model. However, in reality, any inter-port leakage signal exists in the measurement jig, and thus such omission is a major factor of a residual error in relative error correction.
To solve the above-described problem, Japanese Patent No. 5246172 discloses a relative error correction method that can also correct a difference in the inter-port leakage signal between measurement jigs in measurement of optional N ports equal to or larger than two ports. The number of ports included in a standard specimen to be prepared for the measurement of optional N ports and necessary for performing the relative error correction method disclosed in Japanese Patent No. 5246172 needs to equal the number, which is at least five, of measurement ports having different properties.